1. Field of the Invention
The present invention relates generally to information distribution systems and methods for delivering interactive information services. In particular, the present invention relates to a system and a method for automatically detecting and correcting defects in a transmission channel of an interactive information distribution system. Still more particularly, the present invention relates to a system and method for correcting defects in a transmission channel of an interactive information distribution system that does not require any additional hardware.
2. Description of the Related Art
Recent advances in digital signal processing techniques and, in particular, advancements in digital compression techniques, have produced a number of ways to provide new digital services to a subscriber""s home via existing telephone and coaxial cable networks. For example, it has been proposed to provide hundreds of cable television channels to subscribers by compressing digital video, transmitting the compressed digital video over conventional coaxial cable television cables, and then decompressing the video at the subscriber""s set top terminal.
Another proposed application of this technology is a movie-on-demand video system in which a subscriber communicates directly with a video service provider via telephone lines to request a particular video program from a video library and the requested video program is routed to the subscriber""s home via telephone lines or via the coaxial television cables for immediate viewing.
However, one particular problem in information distribution systems is maintaining a level of quality and uninterrupted service to subscribers. Whether such systems are digital, analog, interactive or unidirectional, they are subject to equipment failures that can interrupt the information services being provided. Most often such equipment failures are first detected when a subscriber calls the system operator to complain about the lack of service. The system operator must then determine which of a myriad of system components is defective and dispatch service personnel to correct the problem. Thus, there is a need in information distribution systems of a way to ensure level of quality and uninterrupted service to subscribers.
One approach in the prior art has been to provide redundant hardware that can be switched on when a particular component fails to provide fault tolerance. However, such an approach obviously doubles the cost of implementing an information distribution system, and can be prohibitively expensive. In interactive system, some redundant hardware must be provided to accommodate requests for particular content from the subscriber. Such systems are typically optimized to provide the minimum amount of hardware necessary to service the requests from subscribers at peak request times without affecting the quality of service to subscribers. It should also be noted that in such interactive systems, there is a return path of communication between the subscriber/terminal and the system. Even in such systems, failures to provide quality service may occur in the servers, the cable plant, the modulators or the set top terminals. Thus, there is a need for a system that can identify defective components and take corrective action to restore uninterrupted service as soon as possible. The best solutions would occur without affecting the service provided to the subscriber.
Therefore, there is a need for a system and method that provides a particular level of service. More particularly, there is a need for a system and method for automatically detecting defective communication channels and correcting the defect so that a particular level of service is maintained.
The present invention overcomes the deficiencies and limitations of the prior art with a system and a method for detecting and correcting a defective transmission channel in an interactive information distribution system. An interactive information distribution system according to the present invention includes a customer management system, a network management system, a resource manager and video server, a session control manager, a plurality of digital video modulators, a plurality of modems, head end equipment and a plurality of set top terminals or boxes. More particularly, the session control manager includes a defective channel detection module, a channel re-allocation module, and a replacement-signaling module in addition to other applications and an operating system. The session control manager is coupled to receive signals from the plurality of set top boxes, and coupled to control the digital video modulators and the assignment of communication channels to nodes. The defective channel detection module receives signals from the plurality of set top boxes, and based on the error rate and other factors determines if any of the communication channels used by the digital video modulators are defective. Upon determining that a particular communication channel is defective, the defective channel detection module signals the channel re-allocation module. The channel re-allocation module, in response to a signal from the defective channel detection module, re-allocates the streams being transmitted over the defective communication channel so that they are transmitted over the other communication channels. The defective channel detection module also signals the replacement-signaling module. The replacement signaling module identifies the defective digital video modulator and transmits this information to the network management system which in response follows a pre-defined procedure such as paging service personnel to replace the defective digital video modulator.
The present invention also includes a method for detecting and correcting a defective transmission channel comprising the steps of: monitoring communication channels for errors, detecting an error in a communication channel, determining whether the communication channel upon which the error was detected is defective, determining the digital video modulator servicing the channel, determining whether there is another digital video modulator, re-assigning the communication channel to the other digital video modulator, and signaling that a particular digital video modulator needs replacement.